1. Field of the Invention
The present invention relates generally to devices for deflecting rain from the windshield of a moving vehicle and, more particularly, to such devices for use with an automobile.
2. Description of the Prior Art
The problem of removing rain from an automobile windshield to permit its safe operation in inclement weather has presented itself ever since the automobile was first invented. Although reciprocating windshield wipers have almost universally been used to solve this problem, they are far from a perfect solution. For example, the conventional wipers in use today only remove the rain from the windshield of a moving vehicle after the rain has been struck by the windshield, and they are not effective in preventing the rain from being struck by the windshield in the first place. As a result of rain drops splattering when being struck by the windshield of a moving vehicle, the driver's line of sight is greatly distorted and reduced, and during hard rains, is almost totally abscured causing many drivers to stop, and in addition causing many vehicle accidents. Consequently, any device which could provide a clearer vision zone on a vehicle windshield during a rainstorm would greatly increase driving safety and convenience.
Many devices have been proposed over the years to prevent rain from initially impinging on the windshield of a moving automobile. However, no previous devices disclosed or understood that for an invention to efficiently keep rain drops off the windshield of a vehicle at high speeds, the invention must function as a result of a mathematical relationship between rain shield, forward velocity of vehicle windshield and downward velocity of rain drops. It must also protect from potentially strong air pressure as a result of high speeds. For example, U.S. Pat. No. 1,126,754 to Griefen discloses an adjustable storm shield which is movable between an inoperative position above the windshield and an operative position angularly oriented relative to and placed in front of the windshield to prevent snow or rain from impinging on the windshield. Similarly, U.S. Pat. No. 1,645,416 to Collier discloses a pivotal sunshade which also functions as a storm shield when in an operative position. Also similar is U.S. Pat. No. 1,416,112 to Miles which discloses a rain shield that swings up and out and down and attempts to deflect the rain and air flow downward.
The storm shields disclosed in Griefen, Collier and Miles, supra, have a fixed longitudinal position relative to the windshield when the storm shield is in its operative rain deflecting position. Also the storm shields, shield 12 of Griefen, canopy and shield 3 and 6 of Collier, shields 5 and deflector 7 of Miles have no empty space between windshield and storm shield for relief of air compression stress; nor the shields extend a substantial or variable distance in front of their windshields to account for the mathematical relationship between rainshield, speed of falling rain drops, relative to forward speed of vehicle's windshield. Although such storm shields might function adequately at certain low vehicle speeds or rainfall quantities, they will not keep rain off the windshield when the speed of the vehicle increases substantially or when the rainfall quantity with high winds exceeds predetermined minimums. In addition, the storm shields of Griefen, Collier and Miles are generally mounted on the vehicle by means of a bracket structure which traps air impinging against the windshield underneath the storm shields. This presented no particular problem at the speeds at which vehicles traveled at the time these patents issued. However, at the greatly increased vehicle speeds of today, the use of such a storm shield would involve many problems because of the shear stresses imposed on the bracket structure due to the extreme compression of air underneath the storm shield caused by the high vehicle speeds; and, if they were extended out further from the windshield, there would also be a safety problem of air dynamic stability of the vehicle.
U.S. Pat. No. 1,479,375 to Crowell illustrates another type of device for preventing rain from impinging on an automobile windshield. In such a device, a pivotally mounted plate is turned to a position parallel to the windshield thereby creating an air vent. Such an air vent induces a flow of air upwardly along the windshield; any raindrops entering the air vent are supposedly carried upwardly in the flow of air clear of the windshield. In addition, U.S. Pat. No. 2,206,793 to Staubly and U.S. Pat. No. 2,570,399 to Smith both disclose sun visors which are adjustably movable relative to the windshield. However, the structures shown in these latter three patents are not adapted to prevent rain from impinging on the vehicle windshield regardless of the vehicle speed or rainfall quantity.
These and other such devices of the prior art will not work efficiently as a result of the varying speeds of vehicles causing the windshields to strike a greater and greater number of rain drops per second as the speed of the vehicle is increased, whereby, the rain drops will be struck by the windshield of a vehicle from a forward direction, rather than the windshield being struck by the rain drops from a downward direction as these other patents attempt to provide for. This is readily understood when looking at the disclosures of this invention in FIG 4 and the following detailed description, particularly that with respect to FIG. 4.